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rpmdiag, Tech and Instructor
Category: Ford
Satisfied Customers: 7722
Experience:  Since 1975
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I have a 1996 Ford F 150 2 wheel at idle it runs rough apply

Customer Question

I have a 1996 Ford F 150 2 wheel at idle it runs rough apply to gas it shuts off replace the fuel pump spark plugs still does the same thing
Submitted: 1 year ago.
Category: Ford
Expert:  rpmdiag replied 1 year ago.

Hi, I’m Ron and I’ll be helping you today.

Before we get started though,Please understand that I don't know your skill level or tools you have to assist us. Also understand that I can't see,smell, hear or touch the vehicle either, so your patience is appreciated. JA is a great place, but it does NOT replace a shop. My goal is to make you happy and get a great rating in return for my time. Sometimes I have to give you bad news that I know you didn’t want to hear, so please don’t shoot the messenger.

Check your fuel pressure anyway with a gauge, and also check the TP sensor. It may have a flat spot in it that will also cause this. Check for vacuum leaks and check the idle air control motor too. See attachment showing a bad TPS.

Thanks, Ron

Customer: replied 1 year ago.
it has 38 PSI pounds of fuel pressure disconnect the pressure regulator it has 42 and check the TPS and map sensor the mass air flow sensor put new plugs in it and still rough idle give it gas it stalls
Expert:  rpmdiag replied 1 year ago.

Okay, you want to check compression in case we have a low cylinder. It sounds like you have checked and replaced a lot of things already. Good job.

Thanks again, and please don't forget to rate me and keep this link in case you need me again later on.


Customer: replied 1 year ago.
did not replace all of them with new ones some are used
Expert:  rpmdiag replied 1 year ago.

That's okay, if it didn't make a difference, then that wasn't the problem anyway. Go ahead and check that compression, we may have valve issue.


Expert:  rpmdiag replied 1 year ago.

Also check your injectors for a bad one that's not firing. Guess I'm ready to be rated now:)